Updated 7:03 p.m. | President Barack Obama, back in Washington for a day of meetings in the midst of his August vacation, on Monday reported "progress" in the expanded campaign of U.S. airstrikes on Iraqi insurgents near Mosul, and again called for calm in the riot-torn streets of Ferguson, Mo.

He announced that Attorney General Eric Holder will travel to Ferguson on Wednesday to talk with local leaders about the riots that have rocked the St. Louis suburb since the Aug. 9 police shooting of an unarmed black teenager.

Asked about the militarization of American law enforcement that some have said is exacerbating clashes between police and protesters in Ferguson, Obama said it may be time to review the use of federal dollars to purchase surplus military vehicles and gear.

"There's a big difference between our military and our local law enforcement," he said. "And we don’t want those lines blurred."

Some civil rights leaders have urged the president to speak out more forcefully on the shooting of Michael Brown, but on Monday, Obama instead called for restraint on the part of both police and protesters. "While I understand the passions and the anger that arise over the death of Michael Brown, giving into that anger by looting or carrying guns, and even attacking the police only serves to raise tensions and stir chaos. It undermines rather than advancing justice," he said.

"Let me also be clear that our constitutional rights to speak freely, to assemble, and to report in the press must be vigilantly safeguarded: especially in moments like these. There’s no excuse for excessive force by police or any action that denies people the right to protest peacefully."

The president also reiterated that U.S. action in Iraq against the Islamic State rebels, who are also known as ISIS or ISIL, will be limited — though he acknowledged that defeating ISIL could "take time."

"Today, with our support, Iraqi and Kurdish forces took a major step forward by recapturing the largest dam in Iraq, near the city of Mosul," he said.

"Let’s remember, ISIL poses a threat to all Iraqis and to the entire region. They claim to represent Sunni grievances but they slaughter Sunni men, women and children. They claim to oppose foreign forces but they actively recruit foreign fighters to advance their hateful ideology.

"So the Iraqi people need to reject them and unite to begin to push them out of the land they have occupied, as we’re seeing at Mosul Dam. And this is going to take time. There’re going to be many challenges ahead."

He said the administration had consulted with Congress about the strategy.

Earlier, two top Republican senators who have consistently criticized the president's handling of the rise of the Islamic State insurgents praised Obama's decision to ramp up air support for Iraqi and Kurdish forces.

“We applaud President Obama's decision," said Sens. John McCain of Arizona and Lindsey Graham of South Carolina in a joint statement. "The success that we and our Iraqi partners have had thus far in this operation is encouraging. ... These actions should now be expanded into a broader strategy to degrade ISIS both in Syria and Iraq, as we have been advocating. Without a sustained effort to retake Mosul — a center of ISIS activity in Iraq — and to degrade their home base in Syria, we will lose momentum."

Several news organizations reported last week that Holder's Justice Department had asked Ferguson authorities not to release a surveillance camera video showing the shooting victim robbing a convenience store just minutes before the shooting — a request the police refused.

On Monday, Holder made it clear he was not happy with the locals' handling of the case.

"I realize there is tremendous interest ... but I ask for the public’s patience as we conduct this investigation," he said in a statement after meeting with Obama. "The selective release of sensitive information that we have seen in this case so far is troubling to me. No matter how others pursue their own separate inquiries, the Justice Department is resolved to preserve the integrity of its investigation."